Abstract Thebiologicalfunctionandphysicochemicalpropertiesofprotein-basedtherapeuticsaredeterminedbytheir higherorderstructures(HOS).Therefore,itisimperativetoanalyzethethree-dimensionalhigherorder structureofproteintherapeuticsatseveralstagesofthedrugdevelopmentprocesstoensurebothsafetyand efficacyofthedrug.Biopharmaceuticalmanufacturersarerequiredtodemonstratetheconsistencyofthe proteinHOSconformationtotheregulatoryagencies.Moreover,Identifyingthebindingsiteofaproteintoits correspondingantigen(knownasepitopemapping)iscriticalforthedevelopmentofnewtherapeutics, vaccinesanddiagnostics.FoodandDrugAdministration(FDA)guidelinesrequirespecificbindingsite informationbetweenadruganditstargetfortheregulatoryfiling.CurrenttechniquesforproteinHOS characterizationandepitopemappingareslow,expensiveanddifficulttoperform.Wehavedevelopeda technologycalledPlasmaInducedModificationtoBiomoleculesthataddressestheneedoftheindustryfor routinestructural,massspectrometry-basedproteinHOSanalysis.PLIMBgeneratessubmicrosecondbursts ofhydroxyl(OH)radicalsfromwatertolabelproteinsinsolution.TheOHradicalscovalentlylabelsthesolvent accessibleregionsoftheproteinandsubsequentmassspectrometricanalysisrevealssingleaminoacidlevel structuralinformation.Awaytoquicklyandefficientlyanalyzehigherorderstructuresofproteinsonabenchtop scale,PLIMBwillenablefasterdevelopmentofproteintherapeutics,throughoutthedrugdiscoveryprocess.In SBIRPhaseI,wewillprovethefeasibilityofahydroxylradicaldetectionsystemthatwilltightlycontroltheOH radicaldosegeneratedbyPLIMBtoyieldhighlyreproducibleHOSdata.AftercompletionoftheSBIRPhaseI project,wewillcontinuethedevelopmentandvalidationofthePLIMBsystemforcommercialuse.Ultimately, PLIMBwillenablefast,highresolutionstructuralanalysisofproteins,acapabilitywhichishighlysoughtafterin thepharmaceuticalindustry.